The invention relates to an electrical switching and control appartus comprising a plug-in contact strip. It is known to inject the plug pins of such switching and control devices in a plug-in base of insulating material and to make contact between the ends of the plug-in contacts located in the device housing and a printed circuit board. The printed circuit board carries one or more so-called hybrid plates with electronic circuit elements (DE-OS as disclosed in 28 06 558) and/or discrete power semiconductor components and the like.
In another construction known from WO 87/01 007 (R 20142), the power components are fastened, in addition, on a cooling plate which is supported on parallel areas of the adjacent plug-in contacts by an insulating foil and, in this way directs heat generated in the power components outward, via the plug-in contacts, to the electrical lines connected thereto. This construction is costly in production, since the printed circuit boards, the discrete components, and the cooling plate must be prefabricated and preassembled before they are inserted into the switching and control device and soldered with the connection contacts. Moreover, much space is required for such constructions, and they may not be exposed to great shock or vibration stresses when used in motor vehicles because of the relatively large dimensions of the printed circuit board.
In a switching and control device known from U.S. Pat. No. 3,805,117, hybrid plates make direct contact with the plug-in contacts of the device without the intermediary of printed circuit boards. Power semiconductor components in a discrete construction make contact with the hybrid plate which guide off their heat either via a solid enclosure or via another ceramic plate at a steel housing of the device. This construction is also costly, since it requires a metal housing for conducting the heat outward and in which special insulators are inserted for guiding through the plug-in contacts. Moreover, the steel housing is very heavy, which is very undesirable in a motor vehicle construction.